Method of producing lapped joints in piston-rings.



M. L; DUNHAM. METHOD OF PRODUCING LAPPEDJOINTS IN PISTON RINGS.

APPLICATION FILED AUGJI. 19H.

Patented June 11., 1918.

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MILLARD L. DUNHAIVI, OF NEW YORK, N. Y.

Specification of Letters Patent.

Patented June 1111, 1191s.

Original application filed October 26, 1916, Serial N 0. 127,778. Divided and this application filed August 11,

' 1917. Serial No. 185,654.

To all whom it mag concern:

Be it known that I, MILLARD L. DUNHAM, a citizen of the United States, and resident of borough of Manhattan, in the city, county, and State of New York, have invented certain new and useful Improvements in Methods of Producing Lapped Joints in Piston-Rings, of which the following is a specification.

This invention relates to piston rings, and my improvement has particular reference to a piston ring having agas tight, sealed joint, and a novel method for creating said joint in a single mechanical operation.

The present application is a division of my earlier application, Ser. No; 127,778.

In brief my improvement consists in means for forming angular recesses in the opposed free ends of a divided piston ring, the projecting material of each-ring end, where recessed, engaging, respectively, with the opposed recessed portion of the other ring end, and said end portions having opposed curved engaging surfaces to enhance the efliciency and durability of the joint.

The longitudinal seats of the joint are formed at the respective ring ends by cutting away the ring material obliquely at the ends in a transverse direction, whereby, in a ring whose cross section is rectangular, production of the recesses aforesaid leaves terminal portions which are triangular in cross section, and whose hypotenuses relpresent the meeting faces which comprise t operation, comprises a may be driven at the same -35 'olnt.

J The mechanical means whereby my improved sealed-joint is produced in a single pair of cutters arranged in a machine to operate upon opposite surfaces of the ring held between them; and a circular saw or separating cutter arranged intermediate said oppositely acting cutters. The said cutters and saw, which time, are so arranged as to simultaneously produce opposite recesses in 'a continuous ring, and also to cut through and divide said ring between the recessed portions thereof. The faces of the cutters or of the cutter teeth, respectively, may be longitudinally concaved and convexed, that they may impart to the suri faces they act upon in the ring ends like curvatures of engaging character, so that when the ring is contracted in service, the

- example,

said surfaces may meet in closed gas tight relationship, and so that said surfaces will not acquire separating angles, through wear.

Other features and advantages of my said invention will hereinafter appear.

In the drawing Figure l is an elevation of a portion of a machine having two cutters and saw.

Fig. 2 is an end View thereof.

Fig. 3 is a plan view of a ring whose ends have been treated in the apparatus.

.Fig. 4 is an enlarged perspective view of a portion of a ring, showing the joint formed therein, and

Fig. 5 is a View of a apparatus.

In carrying out my invention I provide or employ a machine having a pair of parallel shafts, l, 2, spaced apart, and adapted each to carry a cutter, here indicated, respectively, at 3, 4. The said cutters are circular in form and provided each with a plurality of teeth, which operate in adjacent, separated, vertical planes.

he arrangement of said cutters, brief, of such character that one of as 3, will operate upon one. end, as 5, of a divided piston ring; and the other, as 4, will operate upon the otherend, as 6, of said ring. The said cutters operate, respectively, upon the upper and lower surfaces of the ring ends, to cut away ring material, and thereby produce recesses in the ring ends which will. interfit when the ring is closed.

modified form of them,

The faces of the cutters 3, 4, may be curved transversely, as shown in Fig. 1, the cutter 3 having a concave curvature, for

and the cutter 4 a convex curvature whereby the cuts or recesses which they produce, respectively, in the opposite surfaces of the ring ends, will have complementary contours.

The ring to be treated is between the cutters an oblique recess 7 is extending from near the inner peripheral surface, at one side, to near the outer eripheral surface, at the other side, leavlng said end in the form of a triangular portion whose hypotenuse 8 comprises the outer surface thereof.

The end 4 is reversely formed in like manner, with oblique recess 9, its hypotenuse placed obliquely formed in the end 5,

is, in

(see Fig. 2) whereby 8 comprising the inner surface thereof; the surfaces of recesses 7- and 9,-when the rmg is-contracted in use, lying in opposed contact to provide the sealed joint.

By means of the joint described, gas pressures are retained within the combustion chamber of a gas engine without leakage at the joint, because the junction of the oblique surfaces 7 and 9 extends diagonally across the ring section, thereby presenting a complete closure in the ring against the leakage of gas between the ring joint and the piston.

One of the oblique faces, as 7, which is other words, which is formed in the ring and having oblique face 7, extending less than half way through'the ring.

The recess in the other ring end producing the oblique face 9, is formed, on the other hand, toextend more than half way through the material of the ring, resulting in the creation of the knife edges 12 and 13 at the opposite ends of said face 9, which edges 12 and 13 lie, respectively, within the outer perimeter of the ring on its pressure side, and within the inner perimeter of the ring on its non-pressure side.

Thus the knife'edges 12 and 13 of the ring end portion bearing oblique face 9, do not extend out to the ring edges, but are seated upon and within oblique face 7, and protected thereby from wear.

To explain clearly the purpose of the differential faces 7 and 9, I will point to the disadvantages which would result in having said faces terminate in knife edges, viz.: (1.) as involving a construction difficult of correct accomplishment, and (2 as being inadvisable. on account of the liability to wear with those meeting knife edges forming together portion of the ring per- 5d saw or cutter; instead arranging the recess' forming cutters, shown in Fig. 5 at 3, 4;, close together, so that when they have cut away the ring material, to form the recesses, the ring will become divided by that operation, and thus capable of compressing to engage the recessed or lapped ends. In this form of my invention the ring which is the product thereof will have no gap between its extreme ends, and consequently, the cutters 3, 4?, must be of sufficient width to provide recessed clearances which will permit a sufiicient degree of ring contraction for service conditions.

I claim t 1. The method of producing lap joints in piston rings which consists in applying ,cutters to opposite sides of a ring while holding said ring at an oblique angle relatively to said cutters.

2. The method of dividing piston rings and producing lap joints therein, which consists in applying a pair of cutters to opposite sides of a ring While holding said ring at an oblique angle relatively to said cutters; and in applying a dividing cutter to said ring for removal of excess material, intermediate said pair of cutters, at-

the same time.

Signed at the borough of Manhattan, in the city, county, and State of New York, this 26th day of July, A. l). 1917.

MILLARD L. DUNHAM. Witnesses:

F. W. BARKER. A. B. BARKER. 

